The present invention is directed to a system for measuring the amount of crop material to be harvested by a harvesting machine. A scanning transmitter and receiver of electromagnetic radiation identifies the location and intensity of electromagnetic radiation reflected from the crop material located on a field and communicates that information to a controller that determines the amount of crop material to be harvested.
Crop throughput sensors measuring the amount of crop processed by a harvesting machine are used to automatically control crop conveying and/or crop processing assemblies. Crop throughput is also frequently used for measuring the harvest in specific areas or sub-areas. The forward velocity of the harvesting machine can be controlled by a control arrangement in response to the measured crop throughput, such that a desired crop throughput is maintained corresponding to the optimum throughput of the harvesting machine. It is known to locate crop throughput sensors on a harvesting machine. In known systems, crop throughput measurements are performed after the crop has been harvested by the harvesting assembly of the harvesting machine. Because of the time delay between sensing crop throughput and its location in the harvesting machine, sudden changes in the crop throughput cannot be compensated by a corresponding change in forward velocity. As such, crop processing arrangements may become overloaded, underloaded, or jammed.
U.S. Pat. No. 4,228,636 proposes identifying the density of a standing crop on a field by using ultrasonic sensors mounted on a harvesting assembly. The sensors are arranged to sense standing crop located immediately in front of the cutter bar. A transmitter arranged on the side of the crop intake arrangement emits ultrasonic radiation that is propagated over the width of the crop intake arrangement. The loss of intensity of the ultra-sonic radiation as well as their propagation time detected by the receiver located opposite the transmitter and caused by the crop stand is evaluated and converted into a control signal. Due to external disturbance effects and error possibilities, ultra-sonic sensors have not been proven worthwhile in practical applications.
EP 0 887 660 A describes a harvesting machine that is equipped with a laser distance measuring arrangement. The laser distance measuring arrangement is located on the operator""s cab and continuously scans a region located several meters ahead of the harvesting machine. The cross section of a windrow of crop material to be harvested by the pickup platform is evaluated on the basis of the profile of the windrow located in front of the harvesting machine. The edge of the windrow is identified on the basis of a sudden contour variation. The height of the windrow is determined on the basis of the measured distance values. Here the disadvantage is the fact that only the outer contours of the windrow are considered. A relatively dense windrow cannot be distinguished from a relatively sparse windrow with the same height.
U.S. Pat. No. 6,095,254 is directed to an agricultural machine with a boundary edge detection system. A laser sensor scans a region located ahead of the agricultural machine to detect and monitor the boundary edge. The boundary of the operation is recognized on the basis of the propagation time and the intensity or the phase shift of the reflected light. The arrangement described is not appropriate for the measurement of the amount of crop material to be harvested.
It is an object of the present invention to provide an improved system to measure the amount of crop material to be harvested prior to the crop material being taken up by the harvesting assembly of the harvesting machine.
The crop material to be harvested is exposed to electromagnetic radiation from a scanning device (particularly laser radiation). A receiver in the scanning device detects the electromagnetic radiation reflected by the crop material to resolve its location or its angle. In addition, the receiver measures the intensity of the reflected electromagnetic radiation. The receiver is in communication with a controller. The controller calculates the amount of crop material to be harvested based on the location and/or angle signal, and the intensity signal.
The receiver produces an at least one-dimensional signal resolved by location or angle. A two-dimensional signal taken by a camera is also conceivable. Here the transmitter and the receiver can be moved or pivoted in a manner known in itself together step-by-step or continuously over a measurement region, or only one of these. The controller has been provided with information as to which location or angle is to be associated with the signal received by the receiver. The use of a row of transmitters and/or receivers arranged alongside each other is also conceivable. There is also the possibility that a laser distance measurement sensor can be used in which the transmitter and/or the receiver is not rotated, but a mirror rotating continuously or step-by-step is used to scan the visible region. An angular region of up to 180xc2x0 can be scanned. Such sensors are available from the Sick A. G., D-72796 Reute, under the designation LMS.
The invention proposes that the receiver detect the intensity or the amplitude of the reflected radiation that is a function of the number of plants per unit area and the dimensions of the plants. The measured intensity is considered in the determination of the amount of crop material to be harvested.
From the location and/or angle signals and the intensity signals the amount of crop material to be harvested can be calculated. The amount of crop material to be harvested can be defined as the volume of plants standing on a unit area. Thereby the amount can be measured in cubic meters of plant volume per square meter of the field, although other measurement units are also conceivable. It does not matter if the amount is calculated explicitly and transmitted in any particular form, used as an intermediate result in a further calculation or is incorporated in a calculation of the magnitude of an amount depending directly or indirectly on the amount. In this way with a known width of a harvesting assembly and a known forward velocity an expected crop throughput can be determined from the signals of the receiver.
Using this system an exact determination of the amount of crop material to be harvested can be calculated. Based on the known width of the harvesting assembly and the forward velocity of the harvesting machine the predicted crop load on the harvesting machine can be determined. This predicted crop load can be compared with an optimal crop load, and the forward speed of the machine adjusted accordingly to follow the optimal crop load. The predicted crop load measurement is performed at a distance ahead of the harvesting machine, so that in case of a variation in crop density the forward velocity can be adjusted in a timely manner. This increases the comfort of the operation and avoids critical situations in which the machine tends to jam. The conveying and separating processes in a harvesting machine can also be made to conform to the throughput amounts that can be expected in a timely manner, so that the resulting harvest is improved. Particular attention must be paid to the avoidance of jams that result from excessively high crop throughput.
As a rule the receiver is arranged to determine the distance to a point from the receiver and/or the transmitter to which the immediate output signal of the receiver is to conform. By scanning or sampling of a region located ahead of the harvesting machine a profile of the crop material to be harvested can be determined. In the controller, information can be generated about the width and/or the height of the stand of the plants that makes possible a precise determination of the amount.
The moisture of the plants can also be detected by a known moisture sensor, the output of which is communicated to the controller. The sensor can be arranged in the harvesting machine and detect the moisture of plants already harvested. The use of a sensor operating without contact, that operates, for example, with infra-red radiation, in order to detect the moisture of the plants before the harvesting process, is also conceivable. The moisture contains information about the density of the stand of the plants, that is, its mass per unit volume. On the basis of the measured values of the amount and the moisture, the mass density of the plants can be determined thereby (in units of plant mass per unit of area). If the width of the crop intake arrangement and the forward propulsion velocity are known, the mass throughput that is to be expected can be determined.
Dust in the air and on the plants are disturbance magnitudes whose effect can be largely eliminated by comparing the amount of crop material measured by the scanning device with crop throughput values calculated by sensors located on the harvesting machine. Therefore it is preferred that the controller be connected with an additional crop throughput sensor that measures the crop throughput in the harvesting machine. Crop throughput sensors have been proposed that measure the drive torque or the slip at the threshing cylinder or at the straw chopper. Position sensors on the feeder house, sheet metal baffle plates in the grain elevator, microwave sensors in the flow region of the crop, or sensors measuring the spacing between the pre-compression rolls may also be used to measure crop throughput.
The crop throughput values derived from the measurement values of the scanning device and the throughput values measured by the crop throughput sensor can be compared. In case of a deviation between the measured values for the crop throughput an error message can be transmitted that can instruct the operator to clean the transmitter and/or the receiver.
The crop that corresponds to the signal measured by the receiver interacts as a rule with the crop throughput sensor in the harvesting machine only after a time delay. It is appropriate therefore to consider the time delay between the two measurements in the controller.
It is also conceivable that the measurement value of the crop throughput sensor be used for calibrating the magnitude of the value calculated from the scanning device. Calibration is possible in which the mathematical connection is determined, for example, in the form of a correction table or curve between the magnitude determined from the measured values of the receiver and the measured value of the crop throughput sensor. Here the connection can be determined completely anew after a certain time interval so as to correspond to the immediate conditions (for example, optical qualities of the plants conditioned by weather conditions, time of day, moisture, type of plant, type of ground and ground condition, etc. as well as condition of the scanning device). In addition, with sufficient data, an expert system can be used to calibrate the scanning device. The controller can also be provided with information about the type of crop material to be harvested. The value of the amount generated from the signals of the scanning device is recalculated on the basis of a correction value determined by the data. In the measurement and/or the calibration according to the process described the height of cut of the cutting head can also be considered which can be measured by sensors on the cutting head itself or by the angle of the feeder house. The height of cut influences the amount of the straw taken up, but does not affect the amount of grain. If crop throughput sensors are used which measure only the grain throughput, this correction is worth considering.
As explained above, the controller is able to recognize boundaries of the crop material to be harvested. Accordingly it can be connected with a steering arrangement and guide a harvesting machine automatically along the edge of the crop material to be harvested.
Furthermore, the amount values provided by the controller can be used as input for the forward propulsion velocity of a harvesting machine. They can also be used to control the velocity of a crop conveying arrangement (for example, that of a feeder house) and parameters of crop processing arrangements (for example, the gap of a thresher cylinder and/or the rotational speed of the threshing cylinder). The amount values can also be referenced against their location in a field to generate a crop map.